The formula for losing weight is second-grade arithmetic: Calories in must be less than calories out. But the burn rate of these calories is graduate-school chemistry, the result of a complicated interaction between cells and compounds. The mystery of metabolism helps sell fad diet books and fuel excuses for fatties and skinnies alike.
"It's easy to eat more than you need, and to say, "I don't understand why I'm gaining so much weight; I must have a slow metabolism," suggests Beth Gold, a research specialist who works on weight loss with the University of Vermont's Nutrition & Food Sciences department.
But playing dumb about dieting may be getting harder with the advent of devices known as BodyGem and MedGem. Handheld tools that measure resting metabolic rate (RMR), these gadgets demystify metabolism and purport to hold the keys to caloric control.
That's no small feat, because metabolic rates can fluctuate wildly -- as much as 900 calories per day between two people of the same age, weight and height, according to Sherri Giger. She's a spokeswoman for HealtheTech, the Colorado-based company that makes the BodyGem device. And within an individual, metabolism can speed up or slow down with weight gain or loss -- another maddening reality of dieting.
While some current studies question the how much strength training affects metabolism, most experts seem to agree that pumping iron is the best way to make your RMR a little more rapid. "You're building muscle, active tissue, which requires calories," says Gold. "But it's not going to be so dramatic that you can drastically alter the number of calories you take in by, say, 400. It's more like a 50- to 100-calorie swing."
Like a lot of people, I've long been mystified by -- and miffed about -- metabolism. As a kid who played plenty of sports, I could eat a whole box of Twinkies without gaining an ounce. But as I grew older, my pants got a bit tighter, and now I watch my brothers go for their fifth slices of pizza while I pick at a salad. Their metabolism seems to run at NASCAR speeds; mine more like an Amish buggy.
Last year I stopped running marathons, which meant I needed to pay even closer attention to calorie consumption, without starving myself. I knew about these handheld devices that test RMR, but wasn't about to shell out $800 for one of my own. So I booked a consultation with Kathryn Evans, owner of Healthy Lifestyles, a weight-loss business in South Burlington that advertises RMR testing on its website.
We met on a Saturday morning at her office, which is beside a Mexican restaurant. The thought of chips and salsa was almost too much to bear, as Evans had told me not to eat anything before our appointment -- no exercise or coffee, either, so as not to throw off the results of the metabolism test.
Evans is almost pixie enough to play Peter Pan -- you'd never guess she once weighed 205 pounds. "I was working a stressful job, and I had two young kids, a household and a marriage to maintain," she said. "I basically wasn't even on my list of priorities anymore, so I wasn't taking care of myself."
After she started to exercise and monitor her food, Evans lost 80 pounds over 2000 and 2001. In 2003 she founded Healthy Lifestyles as a way to offer support, structure and accountability to other dieters.
"On diets, people go through three months of deprivation, and once they reach their goal they breathe a sigh of relief and go back to their old patterns," Evans said before we began the test. "With lifestyle changes, you're doing it more slowly, which is better on the body; you'll lose more fat than muscle and can more fully integrate the changes."
Much of Evans' work focuses on conducting group and individual counseling for dieters, who meet at weekly or semi-weekly $20 sessions to discuss the woes of weight loss. The RMR test and consultation costs $75. "But sometimes people just want that number of their RMR, and they're good to go," she said. One of her busiest times of the year, not surprisingly, is January, when clients are still clinging to their New Year's resolutions.
After a few minutes of chatting, Evans pulled out the BodyGem, which looks like a bloated computer mouse with a mouthpiece attached. She gave me nose plugs so that all my oxygen would travel through the BodyGem by mouth, and told me to create a tight seal with my lips around the mouthpiece. "Like snorkeling," Evans said, amplifying the underwater effect by turning on ocean sounds to help me relax and focus on something other than the fact that I seemed to be sucking on a bloated computer mouse.
I've never taken a Breathalyzer, but I imagine the feeling might be similar -- except it lasted 10 long, boring minutes. I thought about what my magic number would be: 1300? 1400? Finally, the BodyGem beeped and Evans read out my RMR: 1689.
RMR accounts for about 60 to 75 percent of the calories we burn each day just to keep our body systems functioning. Work, digesting food, exercising and any other activity make up the rest. As Evans explained, "If you were to sit in a chair all day and consumed 1689 calories, you would maintain your current weight."
After entering this number into a computer program along with my current exercise level -- about two hours a day -- and moderate job-related activity, Evans determined that if I stayed that active, I could consume 2565 calories per day. The numbers she punched into her computer also spat out my body-mass index, or BMI, which has long been used to determine obesity and susceptibility to weight-related diseases. BMI is a person's weight in kilograms divided by height in meters squared; a healthy range is between 18.5 and 24.9. Mine came out at 23, which seemed a bit high, but Evans explained that many athletes have high BMIs because of their muscular mass. So I was not to worry.
She reminded me of the importance of strength training, and discussed how to monitor my metabolism by tracking what I ate. HealtheTech also sells a nifty software program called BalanceLog, which spits out exactly how many calories you are consuming each day -- provided, of course, that you enter a list of everything you eat into the program.
"It's very painful for people to monitor what they're eating," said Holly Haggerty, a 48-year-old Healthy Lifestyles client from Williston with whom I spoke after my session; she'd lost 60 pounds after learning her RMR.
Instead of buying the $50 software -- which wouldn't have worked with my Macintosh anyway -- I opted to keep a food diary. It lasted exactly half a day. And since I didn't really need to lose weight, my food monitoring fizzled by Christmas. Plus, with an RMR of 1689, compared with Evans' (1200) and Haggerty's (1300), I figured I had a green light to indulge a little more than I'd allowed in the past.
Or so I thought. Recently, a nutritionist friend told me that, judging from BodyGem tests she'd seen conducted in gyms, my number seemed off. Healthetech's Giger confirmed this possibility. "The device is a smart little cookie," she said. "But you really do have to follow the conditions to the letter; it's critical to get a 10- to 15-minute rest before you start the measurement."
Gold's subjects at UVM will often fast for 12 hours and then spend the night at the clinical research center in order to get the most precise measurement; their RMRs are tested when they're still in bed. My number, might have been affected by moving around before the test, Gold explained. She guessed my RMR at somewhere between 1200 and 1400. Still, trying the BodyGem was a good idea, she said. "It's good motivation. You're starting to be mindful of how many calories you need to maintain your weight."
And I'm sticking with 1689. That's 11 Twinkies.